We plan to develop methods for the prenatal diagnosis of sickle cell anemia and thalassemia, to study evolution of the sickle gene in human populations, and to investigate the molecular mechanism underlying abnormal globin production in thalassemia. In prenatal diagnosis, we will search for polymorphism in DNA sequence which can be used for linkage analysis of the sickle gene and the different types of beta thalassemia genes. We will devise methods to analyze directly the nucleotide change in the sickle mutation. We will also use molecular cloning to study the divergence between the nucleotide sequence of the S and C gene to determine their evolutionary lineage. In beta thalassemia, we plan to search for different types of nonsense mutations as the cause for beta thalassemia. We will first utilize the suppressor tRNA assay to detect nonsense mutation and determine the exact mutations by cloning the gene and sequence analysis. In alpha thalassemia, we will study the mechanism of production of the non-deletion type of alpha thalassemia by molecular cloning of the DNA, determination of their structures by sequences analysis, and assaying the function of these genes in in vitro systems.